A typical tub has a floor in which a drain opening is in communication through a plumbing drain line with a sewer. A drain cap member is inserted into the drain opening to close the opening and prevent water from escaping from the tub, and lifted from the drain opening to allow water to flow through the drain opening into the sewer. The rate at which the water flows from the tub is usually from 10.5 to 15 gallons per minute for most household applications. This drain time is unacceptable is undesirably for some applications, for example, walk-in bathtubs holding substantially from 55 to 125 gallons of water.